There has been a significant increase in the number of mobile devices, and the range of functionality provided by these devices. Mobile devices can include such devices as smartphones, wearable devices such as augmented reality headsets or similar devices, watches, or other wearable devices, and handheld computing, reading, and/or gaming devices. These mobile devices provide improved user interfacing and increased functionality by an increasing number of sensors or environmental detection equipment (generally referred to herein as sensors). Many sensors generate an analog output (either a variable voltage and/or a variable current output) that must be first converted to digital form before it can be processed by digital processing components (microcontrollers, digital signal processors, or other processing devices). Examples of sensors can include motion sensors, accelerometers, temperature sensors, gyroscopes, location sensors, light detectors, sound/noise detectors, or other sensors.
Many of the sensors are incorporated into mobile devices where the user has an “always-on” expectation of the device. Thus, a device may be designed to track motion or respond to changes in environment, movement, or other conditions with either no delay or delay that is imperceptible to the end user. The always-on operation of devices with sensors is traditionally accomplished by corresponding always-on amplification of analog signals and analog to digital conversion of the sensor inputs. However, such always-on operation demands power. Decreasing form factors are required to integrate more sensors and more interfaces into modern device. However, as form factors decrease, the electronic components are created with smaller features with inherently smaller gain. Such components must be driven harder to provide adequate signal amplification for the sensors.
Additionally, not all sensors require the same performance from the AFE. Some sensors do not require certain blocks of components to be active to produce an adequate input signal. Certain sensors require higher bandwidth and/or higher gain and/or higher sampling rates than other sensors. However, traditional consolidated AFEs are configured to provide operation for worst-case inputs, and/or are configured for general purpose use and consume too much power for modern wearable or mobile devices (e.g., above a 1 mW power budget). To the extent consolidation has been attempted in AFEs, traditional solutions are not scalable to large numbers of simultaneously recorded sensors without a significant power penalty.
Descriptions of certain details and implementations follow, including a description of the figures, which may depict some or all of the embodiments described below, as well as discussing other potential embodiments or implementations of the inventive concepts presented herein.